Measuring instrument.



I. L. DAVENPORT. MEASURING INSTRUMENT. =AIPLIOATION FILED AUG-18.1908.

925,082. Patented June 15, 1909,

anvantoz THE NORRISPETERS'COH wnsmucrou. n. c.

UNIE STATES PATENT @FFIQE.

ISAAC L. DAVENPORT, OF CAMDEN, NEW JERSEY, ASSIGNOR OI ONE-HALF TO FRANKA. GAVANAGH, OF ASHBOURNE, PENNSYLVANIA.

MEASURING INSTRUIVIENT.

Specification of Letters Patent.

Application filed August 18,

Patented June 15, 1909. 1908. senarno. 4%,106.

To all whom it may concern:

Be it known that I, Isaac L. DAVENPORT, I a citizen of the UnitedStates, residing at- Uamden, in the county of Camden and State of NewJersey, have invented certain new and useful Improvements in MeasuringInstruments, of which the following is a specitication.

This invention has relation to measuring instruments and has for itsobject the provision of a novel instrument for linear measurement whichwill be of simple and inexpensive construction and which can be easilycarried in the pocket and readily employed in making measurements onstraight or curved surfaces.

In carrying my invention into effect; I provide a flat disk of certaincircumference, say six inches, and I place graduations and numerals onone or both fiat sides of the disk adjacent to the edge indicatinginches and subdivisions of inches and I provide the disk with a loosecentral hub by means of which the disk can be held between the thumb andforefinger and rolled along the surface to be measured.

In the accompanying drawing in which I have illustrated my invention:Figure 1 is side elevation of the complete instrument. Fig. 2 is acentral sectional view of Fig. 1.

The instrument as shown in the drawing is composed of a flat circulardisk 1 of any suitable material such as wood, card board, paper fiber,celluloid or metal and of a definite and exact circumference say, forinstance, of a circumference of exactly six inches. The disk 1 hasradially disposed graduations on one or both sides adjacent to its edge,these graduations designating inches and fractions of an inch and beingnumbered as shown. The disk 1 has a hole in its center and on each sideof this hole is arranged a washer 2, these washers being secured to thedisk in any suitable manner, preferebly by means of small pins 3 or theymay be glued, cemented, or otherwise attached to the disk if desired. Ahollow hub t extends through the hole in the center of the disk 1 andthrough the washers 2 and has a flange 5 on each end, this hub fittingloosely in the hole and in the washers so as to turn easily therein.

A stick, lead pencil or other object may be inserted in the hub 4, so asto afford a means for holding the measuring instru ment while the disk 1is being rolled along the surface to be measured, or the hub can be heldduring the measuring operation between the thumb and forefinger of onehand.

In using the instrument, the flanged ends 5 of the hub 4. are graspedbetween the thumb and forefinger or a stick, lead pencil or other objectmay be inserted in the hub and held in the operators hand, and theperiphery of the disk is placed in contact with the surface to bemeasured with the line opposite the numeral 1 of the graduations at thestarting point. The disk is then rolled along the surface to be measuredand if more than one rotation of the disk is necessary, that is if theobject to be measured is more than six inches long, a mental note ismade of the number of revolutions and, finally, when the end of thesurface being measured is reached, the fractional parts of an inch, ifany, are added to the total number of inches gone over, each completerevolution of the disk indicating, of course, a length of six inches,and thus the total length of the object in inches and fractions of aninch is ascertained.

It is obvious that the instrument can be utilized to accuratelydetermine the dimensions of objects which it would be impossible toaccurately measure with a straight rule, as, for instance, thecircumference of a cylindrical object, the circumference of a circular,oval, or irregular opening and a great many other dimensions which couldnot be measured by means of an ordinary straight rule.

The flat sides of the disk 1, present a surface which may be readilyprinted, stamped, or engraved and it is my purpose to utilize thesurface to bear advertising matter, as the device can be made so cheaplythat it can be given away as an advertising medium the advertisingsecured being sufficient remuneration for the cost of manufacture.

The hollow hub 1- has its bearing on the washers 2 and these washerstherefore assist in preventing wear of the disk by its rotation on thehub.

I claim.

1. In a measuring instrument the combination of a circular disk havinggraduations adjacent its periphery and having a hole in its center withwashers arranged on each side of the disk and surrounding the edges ofthe hole in the disk and a hollow hub passing loosely through the diskand adapted to receive in object by which the instrument may he heldwhile in use.

2. In a measuring instrument, the combination with a flat disk having acircumference of definite size in inches, and having numberedgraduations on its flat side inclicating' the circumference in inchesand fractions of an inch, and having a central hole,

10 of Washers attached to the disk on each side of the central hole, anda hub fitting loosely in said hole and said Washers and having flangesexternally of the Washers.

In testimony whereof I have aflixed my signature, in presence of twoWItHQSSQS.

ISAAC L. DAVENPORT.

Vitnesses CHAS. B. CONNOLLY, BLANCI-IE STAPLES.

